Like the thousands of waterbirds he tracks every year, Professor Richard Kingsford migrates annually to NSW's Macquarie Marshes to witness a "great sight of nature: tens of thousands of waterbirds breeding in wetlands".

Frog calls that greeted researchers after the 2009 Black Saturday bushfires were robust in number. But genetic testing has revealed they are alarmingly limited in diversity, catching researchers on the hop.

Divisions within the Baird government over its controversial native vegetation reforms are emerging, with a Liberal MP Bruce Notley-Smith warning they could trigger "further irreversible land degradation".

More polar bears are being shot dead on Norway's remote Arctic islands, where dangerous encounters with humans are getting more frequent as visitors increase and global warming melts the sea ice on which the creatures roam.